The best things I learned about ceramic glazes

The study of ceramic glazes was a challenging summer project, to say the least, but I came away even more impressed by the ingenuity of ancient Chinese potters. The project made me re-assess my views on some of their wares, one category in particular. And I only covered a few Tang and Song ceramics: the others like Yue, Yaozhou, Qingbai and all the post-13th century wares will have to wait, as my new academic term begins in a few days.

I wrote four detailed posts (not counting this one) and I'm sorry if they don’t make light reading: as I said in July, this was something I needed to get my head around. To make up for that, here is a "Best Of" list to give you an idea of the most interesting features. There are embedded hyperlinks in case you’re unexpectedly overcome by a thirst for knowledge!

1. Si, Al, Colour and Flux
Not the members of a Cantonese boy-band but the four things you need in a glaze. Silicon (chemical symbol Si) makes it glassy, aluminium (Al) makes it clingy, and various minerals like iron, copper or cobalt give it colour. But the key component is the flux (such as lead, potassium or soda ash): it is the go-between agent that encourages the other elements to melt easily and coat the pot smoothly without cracking. This is why glazes are often referred to by their fluxes: lead glaze, lime-ash glaze, lime-alkali glaze, etc. More about glaze chemistry here (about halfway down).

2. Iron makes the most amazing colours

From left: Tang sancai horse and rider, Ru dish (upper), Longquan dish (lower), Longquan vase with iron-spot decoration.

We think of iron as a heavy black metal, but all the above objects owe their colours to varying levels of iron in the glaze. The amber-brown shade of sancai ware, the blue-greens of Ru, Guan and Longquan, and of course the iron-spots of Longquan tobi seiji, are all derived from iron. The final colour depends on various things: the percentage content (as little as 2% iron can be enough), the level of titanium dioxide in the glaze (too much makes the iron go yellow), and the temperature and atmosphere of the kiln. Next time you admire a dreamy green celadon, remember that its colour comes from the same mineral later used to make railway engines.

3. Ru is rare, Guan is brilliant…

Ru ceramics are famously rare (fewer than 100 pieces remain), beautiful and staggeringly expensive. But it turns out that the glaze, while lovely beyond doubt, is not unusually complex from a technical POV. It’s a reworking of ancient Shang ash glazes but with a bit of iron and a lot of obsessively careful firing. You could argue that this simplicity is part of its charm but I suspect that the enduring popularity of Ru is more about its rarity and historic links to the tragically deposed Northern Song. More details in the middle section of this post.

Ru ware narcissus bulb planter with uncrackled glaze. China, Northern Song Dynasty, 12th C. 

National Palace Museum, Taipei.

Guan is partly inspired by Ru ware but it’s a very different creature. The abstract patterns of its crackled glaze are bold and modern, yet they also reflect the dynasty's sad past. More importantly, the potters’ idea of using low-silica materials to make this crackle (when the received wisdom was that silica prevented cracking) was a brilliant bit of experimentation, especially when working with unfamiliar southern clays. More info in this post.

Guan dish, D: 22cm. Southern Song, 12-13th C. Met Museum NY

4. But Jun is astounding

The glaze that most impressed me was Jun, a blue ceramic from the Northern Song period. Jun ware has a misty shimmering quality known as “opalescence”, sometimes enhanced with purple splashes of copper pigment. It is not especially rare, and I always thought it was a bit florid by Song standards.

Jun ware dish, Northern Song period, 11-12th C. British Museum (Percival David Collection)

But I hadn’t realised that Jun glaze is not really blue at all. Its colour comes primarily from its molecular structure which scatters blue light in the same way as the Earth’s atmosphere makes the sky look blue. The glaze on its own is straw-coloured but if applied thickly, it can make the underlying object look anything from milky blue (if under-fired) to purplish blue (high-fired). It was not until 1983 that two scientists worked out the chemistry behind this, introducing the phrase “liquid-liquid phase separation” to the world of art history. For more info, see the last section of this post.

While researching these posts, my most frequent question was “how did they work that out?”. How did potters know that adding crumbly white stone to the glaze would make it come out green? I tried asking a couple of modern ceramic artists about their glazes and wow, they clammed up fast, as if I’d asked for their PIN numbers or email passwords. Because of course it took years of work and repeated failures before the glaze finally came right: they weren’t going to just tell me all. Likewise with the potters of the imperial kilns (more to the point, the emperor would have been furious if they revealed the secrets of imperial wares). But I hope at least they would have been entertained by my efforts to study their work. 

Main sources used: Chinese Glazes (1999), Nigel Wood; Science & Civilisation in China, V5 Pt 12 (2004 edition), Rose Kerr and Nigel Wood; Song Dynasty Ceramics (2004), Rose Kerr.

Crackle and bubbles - ceramic glazes of the South

The future looked bleak for the Song dynasty after its defeat by Jurchen invaders in 1125-26. The court fled south to Hangzhou, where the Emperor Gaozong (a master of spin) promoted the use of art and literature to win allies amongst the powerful literati class. Out of this arose the two ceramics most commonly associated with the Southern Song: Guan ware and Ge ware.

Guan brush washer, D: 12cm. Southern Song, 12-13th C. Christies Ltd.

Guan stoneware bears some resemblance to Ru ware, which was closely associated with Gaozong’s father Huizong.  In a way therefore, it acted as a reminder of the legitimacy of Gaozong’s rule. But at a deeper level, Guan (which means "official") is a very different creature, not least because the Hangzhou potters had to learn to work with local materials. For the glaze recipe, they followed more or less the Ru approach, using lime (calcium oxide) as a flux and iron for a bluish tone. But they experimented widely with production techniques, so Guan ware may vary between pale blue, green or tan, and the glaze may look opaque or glassy, depending on kiln temperatures (in the 1200-1250°C range) and atmospheres. The underlying clay bodies are dark and iron-rich, often showing through at the rim and base, a feature known as “purple mouth, iron foot”.

Guan eight-petal lobed dish, D: 17cm. Southern Song, 12-13th C. British Museum

While Ru ware is very subtly crackled, the Guan potters had no such inhibitions. A strikingly crackled glaze is the key feature of Guan, which often looks worn and ancient. The method used to produce this was revolutionary. The southern potters experimented with levels of silica (SiO2) which normally prevents crazing. They discovered that if both body and glaze were low in silica (around 65% instead of 70%), a conspicuous crackle could be achieved under the right firing conditions. Kerr and Wood, not usually given to hyperbole, describe this as “one of the greatest artistic achievements in Chinese ceramic history”.

Foliate dish, described as Ge ware. D: 14cm. Southern Song, 12-13th C. Christies Ltd.

Ge ware (ge as in 哥 or “older brother”) is a famously tricky subject. Many experts believe that what is commonly described as Ge ware is just a paler off-shoot of Guan ware. Ge is not mentioned in any known Song dynasty texts (it's first mentioned in Yuan texts) and no evidence has been found of a separate kiln. The key attributes of Ge (lighter-coloured bodies, more layers of glaze, deeper crackle) can all be explained by variances in production technique – and as we know, the Guan potters were an adventurous lot. The Palace Museum, Beijing, staged an exhibition dedicated to Ge ware in 2017 but even they were careful not to date everything to the Song period. Major auction houses sometimes offer pieces as “Ge ware” (including the ones pictured here) with appropriate caveats. But tellingly, neither of these lovely pieces found buyers at auction, so collectors are obviously cautious too.

Brush washer, described as Ge ware. H: 7.3cm, Southern Song, 12-13th C. Sotheby’s Ltd.

This poses an existential problem for glaze analysis: how do you select a piece for testing if you cannot be sure that it is Ge, because does Ge exist as a separate category in the first place? We know that these pieces also exhibit low silica levels in body and glaze, like Guan. It is worth noting however that the prettiest examples of Ge ware (like the ones shown here) have a distinctive double-pattern of crackle: an inter-woven network of dark and light lines which have been stained for effect, poetically named “gold thread, iron wire”. These intricate pieces argue for Ge’s place among the Five Great Wares. Except of course that they may be Guan. 

Conversely, there is plenty of evidence that Longquan existed in the Song period but it is not listed among the Great Wares, probably for two reasons. First, it was not made in an “imperial” kiln but was widely produced in Zhejiang (the coastal province south of Shanghai) for domestic and export markets. And although well-known in the Song period, it was in the early Yuan dynasty that its reputation was at its height and production boomed.

(Left) Longquan mallet vase, H: 17cm. V&A Museum. (Right) Pair of Longquan funerary urns, H: 25cm. British Museum. Southern Song, 12-13th C.

Longquan (a type of stoneware) is one of the most beautiful and influential of the Chinese ceramics. It is the quintessential celadon, with elegant colouring ranging from duck-egg blue to sea green. It was exported as far as Istanbul, where the Topkapi Palace still has a fine collection; while in Japan every tea-master wanted a Longquan vase to accent his exquisitely minimalist tea-house. Celadons are still made in South-east Asia today, in Chiangmai for example. You can find classic designs like the “twin fish” motif - compare my cheap and cheerful modern replica with a 900-year-old version, below.

(Left) Longquan dish, D: 14cm. Southern Song, 12-13th C. British Museum. (Right) Longquan-type dish, D: 14cm. Probably Thailand, 20-21st C. 

Like most celadons, Longquan gets its colour from iron fired in a reducing atmosphere but analysis also shows a high level of potassium oxide (K2O) as a flux, hence it is referred to as a "lime-alkali" glaze. This thick unctuous glaze was applied in several thin layers between firings, and if the potters got it right, microscopic bubbles would form and become trapped in the lower layers. As a result, the best Longquan glazes have an unusual depth and complexity. Kerr and Wood point out how difficult it must have been to fire each glaze-layer consecutively without them all melting into one. 

Longquan vase with iron-spot decoration, H: 27cm. Yuan dynasty, 14th C. British Museum.

The Longquan potters became more daring with their designs in the Yuan dynasty. For the piece shown above, specks of raw iron were placed on the surface before firing, which resulted in dark brown decorative spots (also seen in wares like Qingbai but the Longquan kilns did it best). These were so popular in Japan that they gave it a name – tobi seiji (“flying spot green-ware”). The trumpet-necked vase shown here from the BM’s Percival David Collection was bought in Japan, where its almost-identical counterpart still resides at the Bridgestone Museum, Tokyo.  

Minimalist cool - ceramic glazes of the Northern Song

After the bold colours of the Tang dynasty, the Song (as seen previously) preferred a more refined aesthetic. Some of China’s finest ceramics were developed in this period: collectors talk about the “Five Great Wares of the Song” - Ding, Ru, Jun, Guan and Ge, to which many would add the beautiful Longquan. The collage below shows examples of all six.

From top left clockwise: Ding, Ru, Jun, Longquan, Ge, Guan

This is a lot to cover, so this post looks only at Ding, Ru and Jun – ceramics that flourished in the earlier part of the dynasty (the Northern Song, 960-1125 AD).

Ding ware, a white ceramic from Hebei, northern China, stands out amidst the typical Song blues and greens. The thin clear glaze is so subtle that it is almost a varnish. The main ingredient is magnesium oxide (MgO), an efficient flux which gives a snug glossy finish and has low expansivity so the glaze can withstand high firing temperatures without cracking.

Ding ware is all about the body, which I was surprised to learn is classed as porcelain because it contains kaolin and is fired up to 1300˚C. I’d always thought of porcelain as a later discovery but according to Nigel Wood, some northern clays are kaolinitic and unusually pure, so early potters could make porcelain as long as the kiln was hot enough. Wood describes early northern Chinese porcelain (around 7th C AD) as “the first true porcelains in the world”.

Ding ware basin. China, N Song dynasty, 11-12th C. Percival David Collection. 

Ding potters worked the clay so thin that it couldn’t sit unsupported in the kiln, so the pots were fired upside-down on a support called a “sagger”. This gave the rim a rough finish, so it was enclosed in a strip of copper which fires into a lovely dark chocolate colour.

Xing ware vessels. Northern China, Tang dynasty. JJ Lally, New York.

Ding ware illustrates the effect of kiln atmosphere on glazes. Its creamy tone results from an “oxidising” atmosphere: where there is enough oxygen in the kiln to oxidise the glaze chemicals. Earlier white wares (like Xing ware, below) are a cool ice-white because they were fired in a “reducing” atmosphere, where the kiln is tightly enclosed and low on oxygen. Early potters used wood-fired kilns which tend to give a reducing atmosphere. Song potters more often used coal-fired kilns which made oxidising atmosphere easier to achieve.

 Ru ware cup holder with finely crackled glaze. China, Northern Song Dynasty, 12th C. British Museum.

Ru ware narcissus bulb planter with uncrackled glaze. China, Northern Song Dynasty, 12th C. National Palace Museum, Taipei.

Ru ware is known for its lustrous blue-green glaze, made for the Emperor Huizong around 1100 AD and wildly desired by collectors ever since. Unlike Ding ware, Ru ware is all about the glaze: the underlying stoneware body is kept simple. The glaze is actually a descendant of ancient Shang lime/ash glazes, using high levels of calcium oxide (derived from wood-ash or limestone) as a flux. But the Song potters added a bit of iron (Fe2O3) which gave that beautiful blue-green when fired to about 1200˚C in a reducing atmosphere. 

It’s almost disappointing to learn that the beauty of Ru comes from something as mundane as iron, albeit in the hands of genius potters. We’re lucky to know this though, as there are fewer than 100 pieces in existence, each worth a king’s ransom (the one below sold for US$37mn in 2017), so even broken shards are hard to obtain for chemical analysis!

Ru brush washer with crackled glaze, D: 13cm. China, Northern Song, 12th C. Sothebys Ltd. 

Ru ware introduces the riddle of the crackled glaze. The technical term for cracks in glaze is "crazing", a fault which usually results in the piece being discarded, but it seems both crackled and non-crackled Ru pieces were equally prized by the imperial court.

Crackle occurs on ceramics if the glaze and body cool at different speeds after firing and the glaze no longer “fits” the body. An effective flux and proper kiln control helps prevent this. Yet most existing Ru pieces are finely crackled, some in ways so delicate that collectors have named the patterns: “cicada’s wing”, “fish scale”, “crab claw”, etc. It is believed that these were defects that later became desirable, the way that Japanese art values imperfections (and wouldn’t it be typical of the Song intellectuals to take that view).

The colour of Ru is compared to “the sky after rain”, which is ironic because it is Jun ware that is truly sky-blue. The colour of the sky is a trick of light through atmosphere: similarly, Jun glaze only appears blue because the glaze bends the light in that way.

Jun dish, Percival David Collection (above left). Jun bowl, V&A Museum (bottom left). Jun vase with copper splashes, Christies Ltd (right). China, Northern Song period, 11-12th C.

The luscious shades of Jun, a type of stoneware, have a cloudy tinge known as “opalescence”. Many pieces also have bold splashes of purple for decoration, derived from copper oxide. My art history class loved Jun ware, because it was so easy to identify in exams!

Scholars love Jun too because the glaze is so complex. Under high magnification, its structure is like caviar made of tiny globules of glass. This is due to something called “liquid-liquid phase separation” (Google if you’re interested) which allows it to diffuse light by a process called Rayleigh scattering: the same thing which occurs when light hits the Earth’s atmosphere. And because blue light-waves are the easiest to scatter, Jun glaze and the sky both look blue. Apparently, when a chip of Jun glaze is held up to the light, it is straw-coloured: there is no blue at all. How is that not genius?

The opalescence was once attributed to phosphorus (which certainly plays a part) but scientists have now found that a high ratio of silica to alumina (around 7:1), plus the right quantity of calcium and potassium oxides, will cause liquid-liquid phase separation and hence the scattering effect. This only works within a narrow range of combinations, called the “zone of opalescence”, but the Jun potters seem to have nailed it.

(Left) Milky blue Jun bowl, D:17.7cm, Sotheby's Ltd. (Right) Darker blue Jun bowl, H: 8.9cm, Asian Art Museum San Francisco

The varied shades of blue do not come from specific chemicals but from different kiln temperatures. Jun is fired in reduction to about 1200˚C. If the piece is underfired (slightly below 1200˚C), the globules of glass are big enough to scatter both blue and white light, giving a milky blue colour like the bowl on the left. At higher temperatures, the globules get smaller and the colour goes to sky blue, lavender blue and even a purplish blue (the AAM bowl above). If the glaze is too thin, it reverts to greenish brown like the rim of the V&A bowl earlier (presumably because it’s not thick enough to scatter blue light).

Tang lead glazes: Sancai ware

And so to the Tang dynasty (617-908 AD), whose most famous ceramic is the glazed earthenware called sancai (“three colours”). Confusingly, there are at least four colours in traditional sancai: green, amber, white (or “straw-coloured”) and blue. The tray or platter below displays the green and amber colours, while the gorgeous horse illustrates the blue and straw shades. Some pieces may have grey, dark brown or black tones.

(Left) Sancai tray. D: 29cm. China, Tang dynasty. Met Museum, NY

(Right) Sancai horse. H: 55cm. China, Tang dynasty. National Museum of Korea 

Sancai is probably the best-known Chinese lead-based glaze, containing 55-60% lead oxide (PbO). We know now that lead is poisonous, but there were reasons for its popularity in ceramics. It is a very effective flux which helps the glaze melt and fit the pot snugly. It gives a lovely shine because PbO has a high refractive index, helping to catch and disperse light. Lead glazes can be made directly from crushed raw materials (like old car batteries) without pre-treatment. And they can be fired at low temperatures: around 950˚ to 1000˚ Celsius, so in Chinese terms it is a “low-fired” ceramic. Actually the unglazed body usually needs a higher firing first – known as a “biscuit” firing. The pot below shows the white unglazed “biscuit” body at the base.

Sancai jar and lid. H: 8.3cm. China, Tang dynasty. V&A Museum. 

Chemical analysis tells us the elements responsible for sancai colours. The amber-brown comes from iron (2%-5% Fe2O3), green from copper (CuO), and blue from cobalt (with a bit of iron). The straw-coloured glaze is quite similar to the amber but with much less iron (up to 2%). The rare grey-black tones are high in copper (5%+), while brown-black tones are high in iron (8%+). 

I’ve found no evidence on the original sources of these colours. Did a potter go for a stroll one day and notice some odd-coloured soil which he used in an experimental glaze? Anyway, here are a few of my favourite sancai pieces.

Sancai camel and musicians. H: 58cm. China, Tang dynasty, 7-8th C. National Museum of China

This fabulous camel carrying a musical troupe was a funerary offering or ming-qi, buried in the tomb of a wealthy Tang official. Note the musicians’ high-crowned hats, large noses and bushy beards, indicating that they are from Central Asia which was the source of all things fashionable at the time.

Sancai horse and female polo player. H: 35.5cm. China, Tang dynasty. National Palace Museum, Taiwan.

Polo was a popular sport for women in the Tang period, so it's likely that this woman’s right hand once held a polo mallet. Several museums (the Musée Guimet in Paris in particular) have figurines of female polo players on galloping horses but they are mostly painted clay, not glazed like this one. Like the camel-riding musicians, this woman’s head is unglazed. This may be because sancai has a naturally runny effect, which looked artistic on bowls and horses, but rather weird on human faces.

“Egg and spinach” bowl. Diameter: 19cm. China, 17th C, Kangxi period. Bonhams Ltd.

The fascination with sancai continued well after the Tang. The dappled pattern on this 17th C bowl, known as “egg and spinach”, was created in the late Ming or Qing period when potters experimented with archaistic styles. I think it looks like something from the psychedelic 1960s. The brownish-purple (“aubergine”) spots are a particular feature, derived from iron and manganese (not a traditional Tang glaze).

Chinese ceramic glazes - a technical detour

I was going to begin with Tang ceramic glazes but like London public transport, some detours are inevitable on this journey.

Firstly, we can’t study glazes while ignoring the underlying body of the pot, as different pairings give notably different results. Traditionally, Western collectors have divided Chinese ceramic bodies into three categories: earthenware, stoneware and porcelain.

• Earthenware is the oldest, dating back to the early Neolithic age (10,000 – 4,500 BC), possibly earlier. The one below from north-east China is dated around 2,500 BC. Like all ceramics, earthenware is made of clay, whose main chemical components are silicon dioxide (SiO2, known as silica) and aluminium oxide (AL2O3 or alumina). Earthenware is fired in a kiln at around 1000˚ Celsius, which is low by pottery-making standards. Primitive earthenware is unglazed but later versions (like Tang dynasty sancai ware) were glazed.

Earthenware ‘hu’ jar. Majiayao culture, China, 2650-2350 BC. Met Museum NY

• Stoneware is also made of clay but with slightly different levels of silica and alumina, and is fired in a much hotter kiln, around 1,200˚ Celsius. It is a strong heavy ceramic, less porous than earthenware and usually glazed, making it more useful for household pots and jars.

Stoneware storage jar. China, 4th C BC. Minneapolis Institute of Art

• Porcelain, the finest type of ceramic, is made with clay that contains or has been mixed with the mineral kaolin. Oddly, kaolin itself is mostly silicon and aluminium too but it strengthens the clay by a miraculous process called hydrogen bonding, allowing pots to be made thin and light yet strong. Porcelain has a glassy (“vitreous”) translucent quality. It may be fired at very high temperatures, up to 1,400˚C. Chinese porcelain is nearly always glazed, though modern potters sometimes make unglazed pieces to show off the fine underlying quality of their work.

Inevitably, the boundaries between these categories may be blurred, with academics tying themselves in knots to distinguish one from the other. Chinese scholars simply divide ceramics into low-fired or high-fired, and then categorise by style and dynasty (which I suspect is becoming the preferred approach).

Glazed ceramics were invented well before the Tang period: in fact, glazed stoneware was known in the Shang dynasty (1600 - 1050 BC). The yellow-green or grey Shang glazes were made from burnt wood ash. Kerr and Wood believe that once technology allowed kilns to get above 1150˚C, calcium and potassium oxides in the ash reacted with silica and alumina to form an “accidental” glaze when bits of ash fell on to the pots. Eventually, potters collected the ash and mixed it with water to make glaze. But we’ll look at ash and lime glazes in later types of ceramic, so I think we can conveniently skip the Shang. 

We can’t skip the subject of glaze chemistry however, and here again, silicon and aluminium are key players. A glaze is a kind of melted glass overcoat for the pot, so silicon - the main ingredient of glass - is vital. Aluminium oxide makes the glaze viscous and gluey so that it clings to the pot. In addition, a good glaze needs a “flux”. Fluxes are chemicals that encourage the glaze to melt at lower temperatures and become more flexible (“expansive”) so that it fits the body nicely and doesn’t crack. Fluxes are usually something alkaline like potash or sodium oxide, but historically one of the commonest was lead oxide, which we now know is poisonous. As seen in the previous post, lead is still used in some rural areas because it is cheap and extremely efficient.

The fourth key element of glaze is colour, which comes from heating various chemicals in different ways. This too may have been an accidental discovery by potters whose local materials had different chemical compositions. The result is further governed by temperature and levels of oxygen inside the kiln (“kiln atmosphere”). This is where the potter’s art really gets going. Common types of chemical are copper (for red or green), cobalt (blue) and iron (red, brown, yellow, green and sometimes even blue). Titanium dioxide (TiO2) interacts with iron to give a yellowish colour (with high TiO2) or a cool green colour (low TiO2). This will come into focus when we discuss green ceramics or celadons.

Ewer with copper red underglaze. China, 14th C. Early Ming dynasty. Eskenazi Ltd.

In practice, of course, early potters didn’t go around chemical-testing their ingredients. Glazes were made by mixing water or liquid clay with crushed ore or soil from a particular place, according to a recipe handed down by predecessors. An experimental potter might try something different and if successful, would invent a new type of glaze.

But this has provided quite enough to chew on for now, so again like London public transport, this post (intended for the Tang dynasty) terminates here.  

Old car batteries and the Tang Dynasty

Though I try to make these posts entertaining as well as informative, the truth is that this blog is also my scrap-book of useful information. Many times I’ve whipped out my phone to refer to a post: perhaps to show someone the new Famen Temple (cue yelps of disbelief), or to check if Mahendravarman I was the father of Narasimhavarman I (yes he was).

So while visiting a pottery-making village in Myanmar recently, I realised that I needed to put down some accessible facts on the complicated subject of ceramic glazes. This arose because I asked the potter (a nice young woman) what type of glaze she used, and she pointed to a pile of old car batteries.

“No, the glaze,” I repeated foolishly, making paint-slapping movements with my hand.

“Yes,” she said, “we grind up old car batteries to make glaze.” She showed us a bucket of what looked like lumpy black soot.

Because of my hazy recall of glaze technology, it was a while before I realised (with horror) that she was using the lead from recycled batteries. This was why her pieces looked a bit like Tang Dynasty sancai ware which has a lead-based glaze. I will make jolly sure that the little jar I bought (see below) never comes anywhere near food or drink. What happens to the potter families, who all seem to work without protective equipment, is anyone’s guess.

 (Left): Sancai lead-glazed jar (H: 19.5cm), China, Tang Dynasty (8th C). Art Institute of Chicago.
(Right): Lead-glazed jar (H: 10cm). Myanmar, 2019.

I had no excuse for not remembering lead-based glazes, as I’ve studied Chinese ceramics for a while and even wrote an essay on Song dynasty crackled glaze. So the next couple of posts will focus on this somewhat arid but crucial subject. Sorry! Normal service will resume eventually.

Probably the finest authority on this subject is Science and Civilisation in China, Vol V Part 12, by Rose Kerr and Nigel Wood, both masters in the field of Chinese ceramics. But what caught my attention on opening this massive tome was the dedication to Dr Lee Kong Chian, the late Singaporean billionaire and philanthropist. It turns out that Dr Lee and his friend Tan Chin Tuan (another heavyweight of Singaporean economic history) were major sponsors of the Science and Civilisation in China project, begun in the 1950s by the Cambridge academic Joseph Needham. This later grew into the Needham Research Institute which specialises in the history of Chinese science and technology. Kerr and Wood’s treatise on ceramics is only one of over 25 volumes published by the NRI on subjects ranging from mechanical engineering to language structures. The NRI is based in a secluded old house in leafy grounds behind Robinson College, Cambridge, and if I were offered even a cleaning job there, I would take it just to spend my days in such idyllic surroundings.

Meanwhile, I must stick to my aim of writing about ceramic glazes, so first stop: the Tang Dynasty!

Ancient deities on the Silk Road

Source: National Museum of Korea

This splendid object is a funerary banner, made of hemp-cloth and measuring about 1.9m. It was found in a 7th century tomb in Astana, a huge ancient gravesite in what is now Xinjiang Province, China. The figures with human torsos and elegantly entwined tails are the goddess Nuwa (on the left) and the god Fu Xi who is variously described as her brother, her husband, or both. They were worshipped as far back as the Warring States period (5th to 3rd century BC) and probably much earlier. I love their flamboyant posture, looking as if they are engaged in a happy dance.

Although the Astana gravesite now lies within China, the whole region was once a kind of no-man’s-land, surrounded by deserts (as it still is today) and dotted with small independent city-states that functioned as trading points along the Silk Road. The nearest settlement to Astana was Gaochang but the largest nearby town was Turpan (or Turfan), 35km west, still a thriving centre today.

Nuwa and Fu Xi boast an impressive portfolio of responsibilities and achievements; they are the kind of gods that you want on your side. Nuwa repaired a hole in the universe and saved the world from a catastrophic flood, after which she restored the human race, either by creating people out of mud (in one version) or by coupling with Fu Xi (in a version derived from regional folktales). Fu Xi was the “first of the great sage-kings and the initiator of man’s emergence from his undifferentiated animal state”.  He taught humans to fish and hunt, and is credited with inventing the hexagrams of the I Ching: the symbolic sets of lines used in Chinese religious rituals.

In tombs of the Han Dynasty (206 BC to 220 AD), the pair were often depicted on walls, carvings and banners. Their role was to maintain the order of the cosmos, ensuring a peaceful universe for the deceased in the afterlife. This is reflected in the instruments they hold: a mathematical compass for Nuwa (whose domain is the heavens, which are circular in Chinese mythology), and a set-square for Fu Xi (whose domain is the earth, which is square or angular). It’s been suggested that their presence was meant to give reassurance to the deceased so that he or she would not try to return to the living world. This might explain why the pair look calm and cheerful, unlike the scary tomb guardians of later periods.

Annoyingly, there seems to be no explanation for their serpent tails. The legends simply describe Nuwa as having a human torso and a dragon or serpent’s tail (a surprisingly common feature amongst female deities across several cultures). In the Han period, it became common to portray Nuwa and Fu Xi as a pair with entwined tails, like the Greek caduceus. But no-one seems to know why. 

Amongst its many mysteries, there are two things about this banner that I find particularly interesting. Firstly, it was one of several found in the Astana graves, all from around the same period (examples below). Fu Xi and Nuwa were most commonly found in Han Dynasty burials, so what were they doing in Central Asian tombs 400 years later?  

Sources: National Museum of India (L), British Museum (R)

The likely answer is that they were a reflection of cultural diaspora, where emigrants maintain long-standing traditions from their home country. Gaochang, the nearest town to Astana, had a large ethnic Chinese population. Turpan had a history of diplomatic relations with China, dating back to the Han Dynasty. A consequence of Silk Road trade was that many Chinese businessmen settled in these towns, and in doing so they kept up old traditions like burial practices that dated back for centuries. The same type of cultural memory exists in migrant Chinese communities in South-East Asia today.

The banner also offers an interesting link to Japan’s involvement in Silk Road archaeology. While European names like Aurel Stein and Paul Pelliot are famous as Silk Road explorers (or plunderers, depending on your viewpoint), there were also three Japanese expeditions in the early 1900s, on one of which this banner was discovered. The expeditions were sponsored by Count Otani Kuzui, leader of a major Japanese Buddhist sect. Ostensibly, the expeditions sprang from a genuine interest in religious relics, but the truth was that national pride was also at stake. As a budding regional power, Japan did not want to be outdone by Britain, France, Russia and Germany who were (literally) carving up the Silk Road. The Japanese teams were even accused of spying, an allegation that lingered for decades: you can read about it in Peter Hopkirk’s brilliant book Foreign Devils on the Silk Road. 

Worship of Nuwa became less common over time, but temples still exist in her honour, and in Hebei Province she and Fu Xi are commemorated in an annual festival that involves eating lots of noodles (perhaps because noodles look like serpents? See below.). For a goddess who mastered mathematics and flood control, repaired the universe, created mankind and survived the Cultural Revolution, none of this should be surprising.  

Source: BBC

Riding into battle on a rhinoceros

In Vienna recently, I had hoped to see the pages of the Hamzanama owned by the Museum of Applied Arts (MAK). Sadly they are not available to the public but the curator kindly referred me to the Google Arts page containing high-definition images of the full collection. In some ways these are better than the real thing as they can be enlarged for poor aging eyes like mine, whereas original folios can only be viewed in low light. Check out the page here.

You may recall that the Hamzanama is a collection of fantastical stories about Amir Hamza, uncle of the Prophet Muhammad (earlier posts here). Derived from medieval Persian legends, these tales of warriors, demons and giants were hugely popular in Mughal India. The young emperor Akbar commissioned a full set of illustrations which are now recognised as one of the greatest works of Mughal art. I like to think that Akbar, still in his late teens, saw this as his personal superhero comic-book. After the decline of the Mughal dynasty, the 12 bound volumes were lost, probably broken up and sold piecemeal. Fewer than 200 of the original 1400 pages or folios are known to exist today, of which the MAK’s collection of 60 is the largest single holding.

Thinking about the similarity with superhero comics, I was taken by the image above, depicting the warrior Qasim fighting with the evil Kayhur, who is mounted on a rhinoceros. A few of you may have watched the film Black Panther, set in a fictional African country where armoured rhinos are used as mounts in battle (see below). There was some excitement on the internet about “war rhinos”, which someone pointed out had already been used in the film 300 a decade earlier. But as far as I know, no-one in this debate mentioned their appearance in a 16^th century imperial Mughal manuscript.

The artists of the Hamzanama show Qasim rather gruesomely decapitating the poor rhino with such force that even Kayhur’s white shield is sliced neatly in half (detail below). The animal appears to be an Indian one-horned rhino, with its trademark big floppy ears. Whatever the artistic merits of the Hamzanama, I’m happier with the film where the rhino is portrayed as a kind of gigantic family pet. It seems to be modelled on an African white rhino, which is also said to be less bad-tempered than the black rhino, though you wouldn’t really want to test this.

Rhinos have never been tamed for riding, of course, but I’m sure the MAK knew this when it purchased the 60 folios at the Vienna World Fair in 1873, describing them as ‘treasure troves of costumes, architecture, devices, vessels, weapons etc, all richly and neatly ornamented’. The seller seems to have been an Iranian prince, though details are sketchy, and in this climate of resentment at Western museums' ownership of Asian art, I don't expect much further clarification. Pages of the Hamzanama have turned up in the oddest places: those owned by the Victoria & Albert Museum were found stuffed into broken window-panes in a Kashmir antique shop. Each page would now be worth over half a million pounds.

I can’t leave without sharing another fabulous and funny image (see below) which supports the ‘superhero’ hypothesis. Two brothers, fighting for the infidel enemy, attempt to frighten the troops by lifting an elephant and tossing it aside. Farrukhnizhad – one of the good guys – sees this and snorts: “Two men to lift one elephant?”. He then picks up the poor elephant himself (the animals really don’t do well here), whereupon the awestruck brothers immediately agree to convert to Islam and join the good side. The name Farrukhnizhad doesn’t have the same ring as Hulk or Iron Man, but for Akbar it probably sounded Marvel-lous.

Reference material: The Adventures of Hamza: Painting and Storytelling in Mughal India, John Seyller and Wheeler Thackston, Smithsonian Institute

Blossoms on ice - the Kangxi blues

Source: Lady Lever Art Gallery

After a nice warm February, the blossom is out on the trees in London – just in time for the return of cold weather. Even before global warming, this must have happened in 17th century China too, perhaps inspiring the motif on this jar from the Kangxi period (1661-1722) of the Qing dynasty.

Many people may recognise this piece – or think they do – as it has been so widely copied over the centuries. The pattern depicts blossoms of the ‘prunus’ family (which includes cherries, plums and hawthorn) against a background of cracked ice. It is believed that this symbolised the approach of spring, with winter ice beginning to melt and early blossoms starting to emerge. In 19th and early 20th century writing, jars of this shape were often called ‘ginger jars’, based on the belief that they were used to hold sweets like candied ginger as gifts for friends and relatives. This particular type of jar was sometimes called a ‘hawthorn’ jar because of its decoration but the preferred description now seems to be the ‘Kangxi prunus’ jar.

From the technical perspective, the jar is notable for several reasons. It is a fine example of underglaze blue decoration, the kind used on blue-and-white porcelain of the preceding Ming dynasty (though it was invented even earlier). This decoration is achieved by painting cobalt-rich pigment onto the raw surface before applying a clear glaze on top and then firing in a kiln. Sounds simple but unless the pigment, glaze, clay, kiln temperature and kiln atmosphere are exactly right, the whole thing becomes a smeary cracked mess. Even the experts at the famous Jingdezhen kilns didn’t always get it right – hence a thriving market today in discarded broken shards (probably the only genuine Chinese ceramics I will ever afford!). But successful examples have gorgeous blue tones with subtle patterns and images somehow held intact under the smooth glaze.

This type of jar is also notable because it sparked a kind of collectors’ mania in the early 20th century. Good examples of Ming blue-and-white were still extremely rare in Europe, so the early Qing dynasty pieces were considered the most desirable. Scholars like Stephen Bushell and R L Hobson wrote about them in glowing terms, and (slightly dodgy) dealers like Joseph Duveen encouraged their millionaire clients to snap them up. Some wealthy collectors proudly accumulated several Kangxi prunus jars, which you’d think would give them a clue about how rare they were (i.e. not terribly). One of them was bought by Lord Astor for 5,900 guineas in 1905, equivalent to about £470,000 today, setting a record price for Chinese ceramics which lasted for decades.

Like other manias, this one soon came to an end, partly because fine Ming blue-and-white wares became better known. Collectors also learned that the prunus jars were predominantly made for export, whereas many Ming pieces were intended for the imperial household, making them more prestigious. In 1997, the same Astor jar was sold at Christie’s for £27,500. Today, an average example may fetch £2000-3000 at auction. The Lady Lever Art Gallery in Liverpool has no less than nine in its catalogue, either purchased by Lord Lever in the early 20th century or gifted by some other wealthy collector. In contrast, the very knowledgeable Sir Percival David (active in the late 20th century) didn’t include any in his collection which now resides at the British Museum. The BM’s solitary example was a gift from Augustus Wollaston Franks, a 19th century collector.

For me, the jar has echoes of the first Chinese ornamental pieces that my parents bought in a department store in the 1970s (the old C K Tang store on Orchard Road, for any Singaporean readers), so I’m quite fond of it. To commemorate its brief heyday, here is a montage of all nine of the jars in the Lady Lever gallery.

A totally unexpected distraction

I started my MA in History of Art last autumn, aiming to keep up the blog posts when possible, but I didn't foresee being totally and utterly distracted by a new field of art: Indian cinema! I don't mean Satyajit Ray's refined intellectual works but popular Hindi cinema like Sholay, the great 1973 movie that launched the masala Western. For this I have to thank the inimitable Professor Rachel Dwyer of SOAS.

As for those of you (and I know who you are) rolling your eyes and hovering over the 'delete' button: fear not, this blog will not become flooded with posts about Karan Johar, Ranveer Singh or Kareena Kapoor. Though if KJo's forthcoming epic about Emperor Aurangzeb turns out any good, I may mention it in relation to Mughal art. And I may make an exception for Zoya Akhtar. But that will be it.

My next post also relates to my MA course, because I was going to do an essay on the Kangxi jar but my ceramics tutor said it didn't fit the brief. So rather than let the research go to waste, here it is (see above).